revision: CH 1 - Number facts and sequences

Definition of words =
integer - a whole number
prime number - only divisible by itself and 1.
multiples - numbers you multiply to a certain number to increase it in equal steps (itself).
(eg. 12 -> 12, 24, 48...)
factors - numbers divisible by a certain number which you can multiple to get that number. Number is smaller than itself.
(eg. 12 -> 1, 2, 3, 4, 6, 12)
rational numbers - numbers that can be written as a whole number, fraction or decimal.
irrational numbers - numbers that the exact value cannot be written.

SEQUENCES-
a) For the sequence 4, 8, 12, 16...
The 10th term is 4 x  10 = 40.
The nth term is 4n.

b) For the sequence (1 x 2), (2 x 3), (3 x 4)...
The 10th term is (10 x 11)
The nth term is n x (n + 1) or n(n + 1).

c) For the sequence 5, 7, 9, 11...
The common difference between each term is 2 so the expression will contain 2n.
The 10th term is 23 (from counting up in 2, to the 10th)
The nth term is 2 x n + 3 or 2(n + 3) [10th term -> 10 x 2 + 3 = 23]

n is the term. :) ALWAYS.